Interlocking system for railroads



- s. N. WIGHT INTERLOCKING SYSTEM FOR RAILROADS Sept. 9, 1941 Filed Sept. 21, 1939 7 Sheets-Sheet 1 ZJZMM ATTORNEY Sept. 9, 1941. s. N. WIGHT INTERLOCKING SYSTEM FOR RAILROADS Filed Sept. 21, 1959 7 Sheets-Sheet 2 Qsne. Y AT v T5 h W mm 2 4 ATTORNEY p 1941- s. N. WIGHT 2,255,142

INTERLOCKING SYSTEM FOR RAILROADS Filed. Sept. 21, 1939 7 Sheets-Sheet 3 FIG. 3.

. INVENTOI g I BY I I Mrfin Sept. 9, 1941. s. N. WIGHT INTERLOCKING SYSTEM FOR R AILROADS 2 .0 o mm t. 4 0E 38 EY U 3 P Em cm W @3 2 m in fM iht e Sept. 9, 1941. s. N. WIGHT INTERLOCKI [NG SYSTEM FOR RAILROADS 1939 7 Sheets-Sheet 5 Filed Sept. 21

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w E6 553 5 9: tutu TTORNEY Sept. 9, 1941. s. N. WIGHT INTERLOCKING SYSTEM FOR RAILROADS Filed Sept. 21, 1959 4 '7 Sheets-Sheet a L. L L L1 L 1 f rvmm muzw .r r W h- J. m N2 2 m w n u m m u u m h a m u \w v n u m n 2 u n v n h m LL-Q W m E 3 1 .V n W w m fl x m w Sept. 9, 1941. s. N. WIGHT INTERLOCKING SYSTEM FOR RAILROADS Filed Sept. 21, 1939 7 Sheets-Sheet '7 INVENTOR Patented Sept. 9, 1941 2,255,,ii2 I INTERLOCKING SYSTEM FOR RAHBOABS Sedgwick N. Wight, Rochester, N. Y., assignor to General Railway Signal Company, Rochester Application September 21, 1939, Serial No. 295,937

"are transferred during the progress of trains so 31 Claims.

This invention relates to interlocking systems for railroads, and it more particularly pertains to an interlocking system in which the setting up of routes for trains can be effected manually immediately for certain track switches and can be deferred through the medium of train describer apparatus for other track switches until the particular train for which the control is intended has reached such other track switch or switches. This application is a continuation-inpart of my prior application Ser. No. 245,383 filed December 13, 1838, which was later abandoned in favor of the instant application.

There are conditions encountered in railroad practice in which trains are to be sorted over one or more facing track switches at the far end of a stretch of single track in accordance with the particular kind or class of such trains. That is, trains of one class are routed over the first track switch in a normal position, and trains of another class, are routed over the first track switch of a group in a reverse position. As an example, the present invention is particularly applicable where a single track section leads from an interlocking plant and at its far end branches into two or more track branches, each branch of which may constitute a separate railroad, the single track section being so long that a plurality of trains may follow each other and occupy the section at the same time. Since there is only one, or only a few, classifying track switches at the far end of the section it may not be desirable to have an operator there at all times or if there is an operator present it may be desirable to at times relieve him of the duty of operating these leaving or classifying track switches; and the present invention contemplates the operation of these classifying track switches in accordance with route control means of the entrance-exit type operated to set up routes in the interlocking plant located at the entering end of the single track section, the operation of the classifying track switches at the far end of the single track section in each instance being deferred through the medium of train describer apparatus until the train for such track switch operation has reached the exit end of the single track section or'at least is not preceded by another train on such section.

An object of the present invention is therefore to provide apparatus controlled by a west interlocking plant for setting up train descriptions in a train describer, which describer may store a plurality of train descriptions one for each train that the order of the descriptions at all times conforms to the order of the trains which they describe, and to provide means to operate the track switch or switches of an east interlocking plant at the leaving end of the single track section to direct each train to its proper branch track upon its arrival. Although the interlocking systems may be of any suitable type, they are preferably of the entrance-exit or NX type.

When traffic is heavy, it may be desirable, under some conditions encountered in railroad practice, to dispense with the train describer apparatus and to alternate train movements overa track switch at the leaving end of the single track means for alternating the position of the first the classifying end is sorted in accordance with the class of train described in the train describer at a particular time, is alternated over that track switch in its two positions at another particular time, and is directed over that track switch at v the discretion of an operator at still another time.

Another object of the present invention is to provide optional selecting means for controlling a track switch or group of track switches at the leaving end of the single track section in order to satisfy the above described means for dispatching trains. Thus, it is proposed to provide a manual selecting leverhaving three positions to select the manual control only of the leaving end or east interlocking plant when in a first position, to select the automatic control of such interlocking plant in accordance with descriptions of approaching trains stored in a train describer when in a second position, and to select automatic control of the interlocking plant so as to send trains alternatelyv over the first track switch in its normal and reverse positions when in a third position. It is also proposed that the i the single track section, which descriptions 555 east interlocking plant be subject to .manual control, irrespective of the position of the control I lever.

The manual control of the interlocking plant at both the entering end and the leaving end of the single track section is preferably accomplished in accordance with the entrance-exit system of control. That is, an operator has only to actuate a button for an entrance point, together with a button for an exit point for any particular route he wishes to set up, irrespective of the number of track switches included between the entrance and exit points thus designated. The entrance-exit system employed in this invention is to be considered an improvement over the system shown in prior Langdon application, Ser. No. 119,641, filed January 8, 1937, and Patent No. 2,148,865, dated February 28, 1939.

The train describer system used in the automatic sorting of trains at the leaving end of the single track section, in accordance with controls set up at the other interlocking system can be of any suitable type, such, for example, as the type shown in the prior application of R. M. Phinney, Ser. No. 111,671, filed November 19, 1936. Although descriptions communicated in that system are characteristic of approaching trains, it is to be understood that descriptions communicated in such a system can as well be characteristic of desired destinations or routes for approaching trains.

Another object of the present invention resides in the provision of a code type selector system incorporated in the train describer system and for transmitting the train description from one interlocking system to the other over a comparatively few line wires, it is however to be understood that in a modified construction the descriptions are transmitted over a larger number of wires without the utilization of code.

Another object of the present invention is to provide a plurality of exit control levers or buttons at the exit point of the interlocking plant located at the entering end of the single track section which plurality of buttons may each describe a particular train or may each define the exit point for a particular train at the interlocking system located at the leaving end of the, single track section or may do both.

When the system is under automatic control for the alternation of routes for approaching trains, it is proposed to have the route for the first approaching train set up manually, or it must have been previously set up by automatic train describer control. When the first train leaves the detector track section, a different route is proposed to be set up for the next following train. Thus the automatic control for the alternation of routes conditions the self-selecting network only when a route is available.

Another feature of the interlocking system at the leaving end of the single track section provided by the present invention is that the selfselecting network can be conditioned by manual control at any time, even when the detector track section is occupied by a train. Such mode of operation provides that an operator can precondition a route while the detector track section is occupied, and that the energization of the self-selecting network under such conditions renders the automatic control ineffective for changing the. route thus preconditioned until the passing train leaves the detector track section.

Another object of the present invention is to provide that the designation of routes by automatic control is only momentary, thus allowing an operator to restore to normal a route already set up by automatic control, and to set up another route by manual control, all without operating the selecting lever to the manual control only position.

A further object of the present invention is to provide that, in setting up a route by manual control, it is necessary to actuate the control button for the exit end of the proposed route only. Such mode of operation is particularly adaptable to conditions where a single entrance point is common to a plurality of routes fanning out in a particular direction from that entrance point, particularly where traflic moves normally in one direction only over the route.

Another object of this invention with respect to the train describer system for controlling an interlocking plant, is to provide means by which an operator can cause the suppression of the Another object of the present invention resides in the provision of means whereby during the setting up of a train description in a train describer the exit control of the NX interlocking system at the entrance end of the single track section is not effected until the train description has been fully setup in the train describer system.

It is also proposed that when the selecting lever is in a position so that the system is under autoautomatic cancellation of train descriptions stored, such suppression being effective only until one train has passed through the interlocking plant in the direction of trafiic for which the train descriptions are received. Such suppression is desirable when an undescribed train is dispatched over a track switch automatically governed by the train describer system.

Other objects, purposes and characteristic features of the present invention will be in part obmatic control in accordance with train descriptions transmitted, the routes are set up for the of the entrance and exit relays of the self-selecting network of the NX system at the exit end of the single track section. It is proposed to set up a route for a first approaching train as soon as the description is received, but when a description for a second train is received before the first train has left the detector track section, the self-selecting network is rendered effective to cause the setting up of a route for the second train, only after the first train has left the detector tracksection. Thus, the automatic sorting of trains in accordance with train descriptions conditions the self-selecting network only when a route is available.

approaching trains by the selective energization vious from the accompanying drawings and will in part be pointed out as the description of the invention progresses.

In describing the invention in detail reference will be made to the accompanying drawings in which like letter reference characters designate parts of a similar character, those parts being made distinctive by preceding and succeeding numerals or exponents, and in which:

Figs. 1 and 2 when laid one above another illustrate the NX type interlocking system located at the entrance end of the single track section into which traific is governed by the signals SI and S2;

Fig. 3 illustrates some of the exit push buttons for the NX system shown in Figs. 1 and 2 together with their associated storage relays etc. which may be considered part of the train describer system:

Fig. 4A illustrates a code type communication system for transmitting a train description from the storage relays shown in Fig. 3 to the storage relays shown at the right hand end of Fig. 4A;

Fig. 43 illustrates atrack repeater relay and line wires for transmitting a train description from the storage relays shown in Fig. 3 to the storage relays of the storage bank 2" shown in Fig.

Fig. 5 illustrates a part of a train describer system showing the train description storage banks 1 and 2 and associated relays;

Figs. 6 and 7 when laid one above another illustrate the track layout at the leaving end of the single track section for operation of which the train describer was provided, together with selfselecting NX network relays and associated relays and devices provided for controlling traffic over the track layout;

Fig. 8 shows a miniature track layout of a modified form of the present invention; and

Fig. 9 shows a portion of the circuit construction of Fig. 6 modified.

The various parts constituting the embodiment of the present invention havebeen shown diagrammatically and certain conventional illustrations have been employed for the purpose of simplifying the illustration and facilitating in the disclosure of the invention, the drawings having been made more for the purpose of disclosure of the principles and mode of operation of the system, than with the idea of illustrating the specific construction and arrangement of parts that would be employed in practice. Thus, certain details well known to those familiar with the art are illustrated in a conventional manner and by dotted lines, and symbols are used to indicate connections to the terminals of batteries or other source of electric current, instead of showing all of the wiring connections to those terminals.

In order to simplify the disclosure of the present invention, reference is made from time to time to functions common to all parts of a similar nature by use of letter reference characters without preceding or succeeding numerals or exponents. It is to be understood that such a reference applies to any parts designated in the drawings by reference characters that are similar except for numerals and exponents associated therewith.

The symbols and are employed to indicate the positive and negative terminals respectively of suitable batteries or other sources of direct current, and the circuits with which those symbols are used always have current flowing in the same direction.

Apparatus Track Zayout.-With reference to Figs. 1, 2, 6 and '7 a main or single track has been shownbetween signals S3 and Sill of two separated interlocking plants in a manner to form at least four possible routes for trains passing from left to right.

The track switches ITS and 3TS are positioned by power operated switch machines. lSM and 3SM of a suitable type such, for example, as the switch machine shown in the patent to W. K. Howe, No. 1,466,903 dated September 4, 1923 The motor of the switch machine SM is controlled in a suitable manner preferably to provide overload protection and other desirable features usually employed in the control of switch machine motors such as is shown for example, in the patent to W. H. Hoppe, et al., No. 1,877,876,

dated September 20, 1932. If the switch machine motor is controlled in accordance with this Hoppe et al. patent, the relay OR is controlled by relay WZ illustrated in Figs. 2 and '7 of the present disclosure. J

The track switches are provided with the usual polar-neutral relays WP for repeating the locked I the reverse locked position of the switch machine- SM. The W? relays are picked up only when energized under either of the above conditions.

Signals have been illustrated for governing traihc through the track layout in both directions, signal SI, S2 and Sill having been provided for governing east bound traffic (to. the right), and signals S3, SH and S52 having been provided for governing west bound trafiic (to the left). Additional signals, not shown, are preferably employed in the single track section connecting signals S3 and Sill. Although a number of different types of signals can be used, such as semaphore type signals and search light signals, the signals illustrated in the present embodiment of the invention are of the type having separate color light units for danger and 'clear indications. A danger indication is normally displayed by the illumination of a red lamp, and a clear indication is displayed by the entering signal for a route set up when a green lamp is illuminated. It is to be understood that a caution indication can as well be provided if such indication is required in practice.

A detector track circuit is provided for each track switch in the usual manner for the energization of the track relays such as ET and 3T, the details of such track circuit have not been shown in order to simplify the present disclosure, because those details are well known to those familiar with the art.

Control machines-Control machines are provided at opposite ends of the single track section one for each interlocking plant for governing trafiic through the track layouts illustrated in Figs. 1 and 6 each of which includes a control panel upon which is constructed a miniature track diagram representative of the track layout for which the system is provided. Upon the track diagrams are located an entrance button NB for each entrance point in the track layout and an exit button XB for each exit point in the track layout. Additional exit buttons shown in Fig. 3 are also employed. The buttons are located at positions representative of the respective entrance and exit points of the track layout for which they are provided. Buttons INB, ZNB, 3N3, IUNB, NE and IZNB have been provided for entrance points at signals Si, S2, S3, Sit, and SIZ respectively, and buttons lXB, ZXB, SXB, HBXB, HXB and IZXB have been provided for exit points at signals SI, S2, S3, Sid, SH and SH, respectively. Special train describing exit buttons SXBl, SXBZ, 3X33, 3XBA and SXBB have also been provided as shown in Fig. 3. These latter buttons are preferably located directly below the exit button SXB on the miniature track layout.

Each entrance button NB is of the push-pull type, and is automatically restored to a normal position after being depressed or pulled out; Each entrance button NB has a contact which is normally closed and remains closed when the button is depressed, but which is opened. when the button is pulled out, and has another contact closed only when the button is in a depressed position. Whenever the button is pulled out from its normal position the normally closed contact is opened. These control buttons may be of a construction, for example, as shown in the application of J. F. Merkel, Ser. No. 158,720, filed August 12, 1937.

Each exit button XB is of the self-restoring push button type, having a contact associated therewith closed only when that button is de pressed.

It is to be understood that other forms of control buttons or switches could as; well be substituted for those illustrated, and that the entrance and exit button contacts for each signal location could as well be combined on one button having distinctive positions or circuit means for distinguishing between actuation for an entrance or for an exit point.

Suitable indicator lamps (not shown) are provided on the miniature track diagram at various points to clearly indicate routes set up through the interlocking plant, the condition of occupancy of the track sections, and the indication displayed by the various signals at the track lay out.

Train describer lamps are also provided on the control panel to keep the operators informed as to the description of the trains leaving one and approaching the other interlocking plant. The illumination of the lamps is governed in accordance with train descriptions set up in the multiple indicating train describer. These train describer lamps are provided to keep the operators informed as to the description of one leaving and several approaching trains, the lamps for each storage bank being similar to the lamps illustrated in Fig. 5. These lamps describe the last train to leave one interlocking plant and a first and second train approaching the other interlocking plant. The lamp associated with the push button relays of Fig. 3 are controlled by relays IP, 2P, 3P and 4P in exactly the same way as the lamps of Fig. 5 are controlled by relays IDSI, iDS2, IDSS and IDSG, respectively. It is assumed that lamps A and B (see Fig. 5) are provided for describing trains of different kinds but of a particular class which all take the same route over the track switch shown in Fig. 6 in one position, and that lamps l and 2 are provided for describing trains of different kinds of another class which all take a route over the track switch of Fig. 6 when assuming the opposite position. Although only two lamps for each class have been illustrated, it is to be understood that other lamps are provided in accordance with the number of different trains of each class to be described.

The lever ASL (Fig. 6) is provided Within convenient reach of an operator, preferably on the control panel, for providing manual selection between the various means provided by the present invention for governing the east interlocking plant located at the leaving end of the single track section. \Vhen the lever ASL is in a center position, the interlocking plant is under manual control only; when the lever ASL is in a left hand position the plant is under automatic control in accordance with the description in the train describer of approaching trains, the manual control still being effective; and when the lever ASL is in a right hand position the interlocking plant is governed by approaching trains in such a manner as to alternate the trains over the track switch in normal and reverse positions, manual control of the interlocking plant also being eifective when the lever is in that position.

Self-restoring cancelling push button CPB (see Fig. 3) and. CAB (see Fig. 5) are provided on the control panels for cancellation of a stored description, and a self-restoring suppression push button SUB (see Fig. 5) is provided on the control panel for suppression of the automatic cancellation by a train of stored train descriptions. Self-selecting network reZays.--An entrance relay NR is provided for each entrance point,

and that relay is energized when the entrance button N13 for that point is depressed in setting up a route. The control of the entrance relay IilNR is such that it is also picked up whenever an exit point is designated, either by automatic or manual control, for signals SI l and S12. This is, however, not the case of the other entrance buttons shown in Figs. 1 and 6.

A relay XR is associated with each exit point and this relay is picked up only when a route is called for between a designated entrance point and a designated exit point associated with that XR relay and then only if no conflicting route has already been set up.

Associated with exit points at signals SH and SE2 are exit repeater relays MK? and IZXP respectively, each of which is momentarily energized in setting up a route including that exit point by either automatic or manual control.

Relay Y is provided as a selector relay to select the control of self-selecting network relays N and R which are provided for causing the positioning of the track switch TS when setting up route.

Train describer reZays.Although there are several types of train describer systems which could be used in accordance with the present in vention, the present invention has been illustrated as applied to an interlocking plant associated with a train describer system such as is shown, for example, in the application of R. M. Phinney, Ser. No. 111,671 filed November 19, 1936. Parts having control circuits different from that train describer system have been shown in detail in this disclosure and certain of the relays of the system have been shown in this disclosure in such a manner as to correspond in arrangement and nomenclature with that prior application to which reference can be made for a more detailed disclosure of the train describer system.

The code type communicating system includes impulse relays PC and NC, lock-out relays LO, line relays F, cycle marking relays SA and SB, incomplete code relays 32, a starting relay C, a half-step relay VP, an execution relay EX and stepping relays IV, 2V, 3V and 4V and a storage bank including relays 3DS and PSP, all more fully described in the Phinney application above referred to.

The relays IDS constitute a storage relay bank, which stores a description code for the first train approaching the interlocking plant. Such description codes are transmitted from the interlocking plant located at the entering end of the single track section by the code type communication system. It is to be understood, however, that the descriptions could as well be designated by lamps in a dispatchers office, or at any other particular point where the description of the approaching trains can conveniently be designated, and that the code type communication system is required only to save line wires.

The relays ZDS provide a storage bank for storing the description codes received for the second train approaching the east interlocking plant. The descriptions stored for the second train approaching are transferred to the storage relays IDS when the first train enters the detector track section containing track relay 3T.

Relays STPA, 3TPB and STPC are slow acting relays provided for the release of the storage relays IDS upon the passage of the first train approaching the interlocking plant and for transferring the train description stored in storage bank 2 to storage bank I.

Relays DP and DPP are provided to aid in the transfer of a description from one storage bank to another, when the first train enters the detector track section. Relay IDP and slow acting relay I DPA in combination provide an execution period for the automatic setting up of each route selected in accordance with the description stored by the relays IDS.

A relay SU is provided for the suppression of the automatic cancellation of descriptions, stored in the storage relays IDS, upon passage of a train through the interlocking plant.

The train describer also includes push button relays P and N, a complete-code relay CSP and a slow acting relay SR. The relays P denote positive and when up signify that the corresponding code storage relay, such as relay 3DS will be picked up and the relays N denote negative and when up signify that the corresponding cod storage relay, such as relay 3DS will not be picked up. The push button EXPB is an execution push button and is used for transmitting a code stored in relays P and N if that is desired while the track circuit containing track relay IT is not occupied.

System devices.-A polar-neutral switch con trol relay WZ is provided for controlling the switch machine ISM and ilSM in accordance with the normal or reverse control selected by the self-selecting relays N and R.

The lock relays L have slow drop away characteristics and are provided toallow the operation of the track switch TS only under safe and desirable trafiic conditions. Although it has been assumed that approach locking is not required for the specific embodiment shown, it is to be understood that additional route locking relay contacts and approach locking relay contacts are included in the control circuit for the lock relay L where such additional locking is required in practice.

Correspondence relays NOR and RCR are provided for repeating the position of the track switch in correspondence with the last initiated controls for that track switch.

A signal contral relay G is provided for controlling each signal. Relay G provides energy for the red lamp of its associated signalwhen in a dropped away position and provides energy for the green lamp of its associated signal when in a picked up position.

The indicating lamp ILI in Fig. 5 is provided to indicate that the suppression relay SU is ener'gized and upon being extinguished signifies that the track circuit containing track relay 3T has just been vacated.

Having thus considered the apparatus provided in accordance with this specific embodispondence relay SNCR ment of the present invention, it is believed that the mode of operation of the system can best be considered by assuming various operating. conditions which would be encountered in prac-' tice.

Operation Normal conditions.-Under normal conditions it is assumed that the signals display a red indication, and that the track switches ITS and 3TS are in their normal straight track position. It is also assumed that the normal conditions provide that the track relays IT and 3T are picked up in accordance with the unoccupied conditions of the detector track circuits, and that no descriptions have been registered in the train describer.

The relays associated'with the self-selecting networks of Figs, 1, 2, 6 and 7 are normally deenergized because it is assumed that there are no routes set up in the interlocking plants. Such a condition is obvious toan operator by the indications of the indicator lamps (not shown) on the control panel. These lamps are assumed under normal conditionsto be extinguished to provide what is conveniently called a normally dark board The manual selecting lever ASL (Fig. 6) for selecting the different types of control for the east interlocking plant is assumed under normal conditions to be in a center position to provide that'the setting up of routes through the interlocking plant can be accomplished only by manual control.

The relays associated with the train describer or train description storing system are normally deenergized with the exception of relays 3TPB and IDPA.

The relay STPB (see Fig. 5) is normally energized by acircuit closed. from through contact '26 of cancel button CAB in a normal position, back contact 2I of relay S'IPA and winding of relay STPB, to Relay IDPA is nor mally energized by an obvious circuit closed at back contact 22 of relay IDP. In the code type selector system shown in Fig. 4A all of the relays are normally deenergized.

The lock relay 3L (see Fig. 7) is energized under normal conditions by a circuit closed from through back contacts I4, I5 and I 6 of signal relays, IIG, IZG and IfiG respectively, front contact 23 of relay 3T, back contact 240i relay 3W2, and winding of relay 3L, to Similarly lock relay IL (see Fig. 2) is energized throughback contacts 2M, 2I5 and'ZIG of signal relays 2G, I G and 3G, respectively, and through front contact 223 of relay IT and back contact 224 of relay IWZ.

In order to simplify the present disclosure, approach locking has not been shown, but it is to be understood that such locking can be provided as required in practice, for example, the circuit for the lock relay L can include front contacts of east and west stick relays corresponding to the relays ES and WS shown in the patent to C. F. Stoltz, Patent No. 2,115,511, dated April 26, 1938. I

A circuit is normally closed for the corre- (Fig. 1) from through a backcontact 25 of relay R winding of relay SNCR, polar contact 26 of relay 3WP, in a right-hand position, and front contact 21 of relay 3WP, to Similarly a circuit is normally closed for the correspondence relay IINCR (Fig. 2) from (-1-) through a back contact 225 of relay R winding of relay INCR, polar contact 226 of relay iWP in its right-hand position and front contact 221 of relay IWP, to Manual control of NX interlocking plant of Figs. 6 and 7.-Assuming the normal conditions of the system to exist as shown and heretofore described, an operator can proceed to set up either of the routes through the interlocking plant in either direction. To consider how routes are set up by manual control for traflic in the assumed normal east-bounddirection, assume an operator to cause the setting up of a route from signal Slll to signal S|2 by the depression of the exit button I2XB.

When button |2XB is depressed, an obvious circuit is closed for the energization of relay |2XP at back contact 28 of button |2XB in a depressed position. The picking up of relay IZXP closes a circuit for the energization of relay |||NR from through front contact 29 of relay IZXP,

back contact 30 of relay 3G, normally closed contact 3| of button IBNB, and winding of relay |0NR, to The picking up of that relay closes a stick circuit from through front contact 32 of relay 3T, front contact 33 of relay IUNR, normally closed contact 3| of button lflNB, and winding of relay WNR, to Connected in multiple in that circuit with front contact 32 of relay ST is back contact 34 of relay 3'IP.

As soon as relay HINR. is picked up, a circuit is closed for the energization of relay IZXR, from through a front contact .35 of relay IUNR,

back contact 36 of relay R winding of relay I2XR, back contact 3! of relay IZNR, and front contact 38 of relay |2XP, to When relay IZXR. is picked up as the result of the energization of that circuit a stick circuit is closed to maintain that relay picked up dependent upon the relay lllNR. for the entrance point of the route being set up. Such a stick circuit is closed from through front contact of relay IONR, back contact 35 of relay R winding of relay .IZXR, and front contact 39 of relay l2XR, to

The picking up of relay |2XR causes the picking up of relay N (see Fig. 7) when a circuit is closed from through front contact 48 of relay |2XR upper winding of relay N and back contact 4| of relay R to After relay N is picked up, relay 3WZ is picked up when its circuit is energized from through front contact 42 ofrelay N and upper winding of relay 3WZ, to

The switch machine 38M is energized for operation to its normal position, if it is not already in that position, by an obvious circuit closed at front contact 44 (Fig. 6) of relay 3WZ. If the switch machine 38M is'already in a normal position as illustrated, when setting up such a route, the lock relay 3L, normally energized, is dropped away when relay 3WZ is picked up to open back contact 24 in the control circuit for that look relay. If, however, the track switch 3TS were in a reverse position prior to the initiation of the proposed route as described above, the relay 3RCR would have been energized at that time by 'a circuit closed from through back contact 42 of relay N winding of relay 3RCR, polar contact 25 of relay 3WP in a left-hand position, and front contact 21 of relay 3WP, to,(-)

Thus, when relay N is picked up in setting up a route from signal Sill to signal S|2 when the track switch 3T8 is in a reverse position, the picking up of that relay N opens the circuit for relay 3RCR at back contact 42 to cause that relay to, .drop away. Relay 3NCR is in a dropped away iii) and front contact 65 of relay lXP, to

position at that time because its circuit is open at polar contact 26 of relay 3WP, so a stick circuit would be closed to maintain relay 3L picked up until the track switch has completed its operation, from through back contacts l4, l5 and N5 of signal relays IG, |2G and lilG respectively, front contact 23 of relay 3T, back contact 45 of relay 3NCR, back contact 46 of relay 3RCR, front contact 4'! of relay 3L, and winding of relay 3L, to As soon as the track switch 3T8 is operated to a normal locked position, relay 3NCR is picked up when energized by a circuit heretofore described, and the picking up of this relay SNCR opens the stick circuit for relay 3L at back contact 45 to cause the relay 3L to drop away because its pick-up circuit had already been opened by the picking up of relay 3WZ at back contact 24.

The dropping away of relay 3L, in setting up a route from signal SH! to signal SIZ, causes the picking up of relay IGG- when a circuit is closed for that relay from through front contact 48 of relay IZXR, front contact 49 of relay 3NCR, back contact 50 of relay 3L, back contact 5| of relay IOXR, front contact 52 of relay lilNR, and winding of relay HiG, to The picking up of relay HJG causes the energization of the green lamp in signal Sill as a result of a circuit closed including front contact 53 of relay IOG. The picking up of the relay IOG also opens its back contact Hi to prevent energization of the lock relay 3L due to closing of back contact 24 of relay 3WZ if this should occur.

If, for some reason, the operator were to cause the restoration of relay N in a manner to be hereinafter described, before the track switch would have had time to complete its operation to a normal position, the relay 3W2 would have been maintained picked up to provide energy for the switch machine SM to complete its operating stroke, as a result of the energization of a stick circuit closed from through back contact 54 of relay 3WP, front contact 55 of relay 3W2, polar contact 55 of relay WZ in a right-hand position, and upper winding of relay 3WZ, to This latter stick circuit is broken at, back contact 54 of relay 3WP when the switch machine has completed its stroke.

A similar mode of operation is employed in setting up a route from signal SHE to signal SI To consider how a route is set up between those route ends, assume an operator to depress button lXB (see Fig. 6) when the heretofore described normal conditions of the system exist. The depression of button IXB causes the picking up of relay IIXP when an obvious circuit is closed at back contact 55 of button ilXB in a depressed position.

The picking up of relay IXP causes the picking up of relay IUN'R by the energization of a circuit closed from through front contact 51 of relay HXP, back contact 35 of relay IOG, normally closed contact 3| of button lllNB and winding of relay IONR, to The picking up of relay IONR closes a stick circuit for that relay as heretofore described.

When relay lllNR is picked up, under such conditions, a circuit is closed for the exit relay 'HXR, from through fi'ont'contact 35 of relay HSNR, back contact 58 of relay N winding of relay HXR, back contact 59 of relay HNR, The picking up of relay HXR closes a stick circuit for that relay from through front contact 35 of relay'lllNR; back contact 58 of relay NF",

of the two wires 18 and to the wire 28 if both Winding of relay HXR, and front contact 6| of relay HXR, to

When relay 1 IXR, is picked up, in setting up a route from signal SEO to signal SH, relay R (see Fig. 7) is picked up when a circuit for the 1 upper winding of that relay is closed from through front contact 62' of relay HXR, upper windingof relay R and back contact 63 of relay N, to

The picking up of relay R causes the dropping away of relay SNCR, if the track switch was last operated to a normal position, by opening its circuit at back contact 25. When front contact 25 of relay R is closed, relay 3W2 is picked up by the energization of a circuit closed from (-1-) through front contact 25 of relay R and lower winding of relay 3WZ, to The picking up of relay 3W2, with relay 3L picked up, causes the energization of an obvious circuit for the switch machine 38M closed at front contact 34, for the operation of the track switch 'STS to a reverse position.

pletion of the operation of the switch machine 38M, relay 3WZ is maintained picked up to com plete the operation of the switch machine by a stick circuit closed from through back contact 54 of relay SWP, front contact 55 of relay SWZ, polar contact 55 of relay 3W2. in a lefthand position, and lower winding of relay 3W2 The dropping away of relay 3L upon the completion of the operation of the track switch STS to a reverse locked position, closes a circuit for relay 3G, from (-1-), through front contact 66 of relay iXR, front contact 6? of relay BRCR, back contact d9 of relay SNCR, back contact 55 of relay 3L, back contact 51 of relay IGXR, front contact 52 of relay ifiNR, and winding of relay IUG, to The closing of front contact 53 of relay 58G causes the clearing of signal Sill.

Having thus described the mode of operation in setting up routes for east-bound trains, it is to be understood that a similar mode of operation is effected in setting up routes for westbound trains. The setting up of routes for westbound trains, however, requires the joint actuation of an entrance and an exit button for each route to be set up, and the mode of operation of the self-selecting network in setting up these routes is similar to the mode of operation described in the above-mentioned patent to Langdon, No. 2,148,865, dated February 28, 1939, to which reference is to be made for further details relative to the self-selecting network. It may, however, be pointed out that the relay 3Y performs several important functions. It prevents energy from feeding from one to the other l9 and gives preference of wires 18 and I9 are energized at the same time, in that picking up of relay 3Y opens the circuit including wire 59 at contact l3 and determines the position of track switch 3T3 by its contact 17. These functions become more important as the track layout becomes more complicated and have been more fully described in the patent to Langdcn,

No. 2,148,865, dated February 23, 1939.

Restoration to normaZ.Tomanually cause the restorationof asignal to stop, and the relays associated with setting up that route to a normal position, an operator pulls out theentrance button NB associated with the entrance point at the signal to be restored.

To consider an example of how such restoration iseifected, assume a route to. be set up as heretofore described from signal SIG to signal SIZ, and assume the operator to pullout button IUN'B (see Fig. 6) to complete the restoration of that route prior to the passage of a train. The pulling out of button IHNB opens the stick circuit for relay IGNR at normally closed contact 3! of that button, and the dropping away of relay away of relay NEG (see Fig. '7) by opening the circuit for that relay at front contact 52. The dropping away of relay IGG opens the circuit for the green lamp in signal SH! at front contact 53 and closes the circuit for the red lamp in signal Sill at back contact 53.

When relay WNR. is dropped away, the stick circuit for relay IZXR (see Fig. 6) is opened at front contact 35 to cause the release of that relay, which in turn, causes the dropping away of relay N (see Fig. 7) by opening its circuit at front contact 49. The dropping away of relay N causes the dropping away of relay 3W2 by opening its circuit at front contact 42, and the dropping away of relay 3WZ closes at its back contact 2 8 the normally energized circuit for relay 3L to cause this relay 3L to pick up and complete the restoration to normal of the circuits associated with the signal Sit and the parts of the system associated with setting up of a route from signal SH) to signal S52.

Restoration upon passage of a train.-An entering signal and the parts of the system associated with a route already set up are automatically restored to normal upon passage of a rain in a much similar manner to their restoration to normal by manual control. The only difference in the mode of operation is that the entrance relay NR is automatically dropped away when the train enters the route set up instead of that relay being dropped away as a result of the actuationof the associated entrance button.

To consider an example of how an entrance relay is automatically restored upon the passage of a train, assume relay IUNR to be picked up and stuck up for a route set up from signal SIB to signal S12. Relay IZXP is down," because the relay was only momentarily energized at the time when a route was'set up, thus the pick-up circuit for relay IONR is open at front contact 29 of relay IZXP. As soon as an approaching train enters the detector track section 3, relay 3T is dropped away, and the dropping away of that relay opens the stick circuit for relay IDNR at front contact 32. Because of the slow action of track repeater relay STP, back contact 34 of relay ETP is not closed until relay IQNR has had time to drop away. The closing of back contact 36 of relay 3T? provides the feature that the stick circuit for relay IBNR can be closed if an operator sets up a governed by those'signals, is automatically effected upon the passage ofatrain in a similar manner. 7

Au om t ett g up 0]; routes alternately;- by

IGNR effects the dropping a NX interlocking plant of Figs. 6 and 7.It has been pointed out that a momentary energization of either of the exit repeater relays I IXP or I2XP is all that is necessary for the setting up of a route for east-bound traffic over switch STS. It has also been pointed out that such momentary energization can be effected by the depression of the exit button associated with each relay XP, and it is obvious when considering the circuit by which relay XP is energized when its associated exit button is depressed, that each relay XP can at any time be picked up by manual control, irrespective of the position of the control lever ASL.

If an operator wishes to provide that trains are automatically sorted alternately over the track switch, he operates the control lever ASL to position alternate to the right. To start the automatic control of the interlocking plant with the lever in that position he must set up a route manually after the operation of that control lever to a right-hand position, if the proper route is not already set up for east-bound trafiic at the time the control lever is operated to that position. In view of the fact that the system for setting up routes alternately is provided .for east-bound trafiic only, it is preferably that the selecting lever ASL be left in a right-hand alternate" position only when routes are set up for that direction of trafiic.

To provide automatic control with the selecting lever ASL in a right-hand position, one or the other of the relays XP is momentarily energized when a first east-bound train leaves the detector track section 3. If the route of the first train includes the track switch 3TS in a normal position, relay I IXP is energized through the circuit selected by the correspondence relay 3NCR. If the route of the first train includes the track switch 3T8 in a reverse position, relay IZXP is energized through the circuit selected by the correspondencerelay SRCR. Thus, it is provided that the routes are automatically set up alternately between signal SI ll and signal S I 2, and between signal SIii and signal SI I.

To consider an example of such mode of operation, assume a route to be set up from signal Sill to signal S42, and the selecting lever ASL to be operated to a right-hand position. The route set up could have been set up by either manual or automatic sorting control. Also assume a train to enter that route to cause the restoration to normal of signal Sill, and the relays associated with the setting up of that route. The presence of the train in the detector track section 3 causes the dropping away of relays 3T and ETP, and when that train leaves the detector track section the relay 3T is picked up prior to the picking up of relay 3TP. The picking up of relay 3T, under such conditions, provides momentary energization for relay IIXP, when a circuit is closed for relay IIXP from through selecting lever ASL in a right-hand position, front contact 68 of relay 3T, back contact 69 of relay STP, front contact II! of relay 3NCR, and winding of relay IIXP, to Thepicking up of relay i IXP, due to such energization, efiects the setting up of a route from signal Sill to signal SI I by the energization of the route control relays in a manner heretofore described. Relay STP is picked up after suflicient time has been provided for the picking up of relay I IXP, and the above described pick-up circuit for relay IIXP is opened at back contact 69 to cause relay IIXP to again drop away, after suflicient time is provided by its slow acting characteristics for the setting up of the route from signal SID to signal SI I.

The next approaching east-bound train, in accepting signal Sis, causes the restoration to normal of the relays associated with setting up the route from signal SIIl to signal SI I, and the restoration of signal Sill to stop. As that train leaves the detector track section at the exit point at signal SII for the route previously set up, an energizing impulse is provided for relay IZXP, when a circuit is closed from through lever ASL in a right-hand position, front contact 68 of relay 3T, back contact 59 of relay 3TP, front contact H of relay .iRCR, and winding of relay I2XP, to As a result of such energization a route is set up, for the next following train, from signal Sit to signal SIZ. Thus the two routes are set up alternately for east-bound trains, irrespective of the number of trains approaching as long as the selecting lever ASL remains in a right-hand or alternate position.

Manual control of NX interlocking system of Figs. 1 and 2.The interlocking system shown in Figs. 1 and 2 is for a single switch similar to that shown in Figs. 6 and 7, but has its switch point facing in the opposite direction. This switch has been designated ITS and the signals governing traffic thereover have been designated SI, S2 and S3. the same as that of Figs. 6 and '7 except for relays which would have been designated IX? and 2X? (not shown) and. corresponding to relays IIXP and IZXP of Fig. 6. It also differs in that the exit push buttons II (B and 2X3 when depressed pick up the relays IR and 2XR directly instead of accomplishing such function through the medium of relays IXP and 2X? (not shown). For this reason all of the relays illustrated in Figs. 1 and 2 have been designated by the same reference letters with distinctive prefixes as corresponding relays of Figs. 6 and '7 and all of the contacts have been designated by the same reference number with a prefix 2. Except for the function performed by the circuits including back contact 38 of relay IBG in Fig. 6 the manual operation of the interlocking system of Figs. 1 and 2 is the same as that of the system shown in Figs. 6 and 7, already described, when the exit buttons IXB or 2X8 are used in combination with and after depressing entrance button 3NB, but is somewhat different when one of the exit push buttons 3XBI, 3X32, 3X33, 3XBA or 3XBB of Fig. 3 are used in combination with entrance button INB or 2N3. This latter operation will be pointed out hereinafter.

Train describer system.Inasmuch as the train describer system used in this embodiment of the present invention is in general mode of operation the same as that shown in the above mentioned prior Phinney application Ser. No. 111,671, filed November 19, 1936, the system has been shown somewhat abbreviated. It is believed,

however, that enough of the train describer system is shown and described in this disclosure to enable those familiar with the art to readily understand its application to the present invention. For a more detailed disclosure of this train describer system, reference is to be. made to the Phinney application above referred to.

Referring to Figs. 3, 4A and 5 when these figures are laid end-to-end in that order illustrate the train describer system when a code type communicating system, such as shown in said Phinney application, is incorporated therein. If, however, Figs. 3, 4B and 5 are laid end-to-end in The wiring for the system of Figs. 1 and 2 is 2,255,142 that order they illustrate the same train describer system exclusive of the code type communication portion and employing instead six line wires for transmitting the train description from the push button relay bank shown in Fig. 3 to one of the storage relay banks shown in Fig. 5.

Referring to Fig. 3 it will be noted that the push button relays are divided to comprise pairs of relays I, 2, 3 and 4 of which each pair includes a relay P and. a relay N. Each relay P denotes a positive code element and each relay N denotes a negative code element, from which it is apparent that for each code description set up on these relays one relay of each pair must be energized and the other relay of each pair must be deenergized. t will also be noted that the depression of any one of the exit push buttons 32ml, 3XB2, 3XBA and SXBB will cause one relay of each pair of the push button relays to be energized. For instance, depression of the push button 3XBI causes energization of the relays IP, 2P, SP and 4N so that this code is that the depression of push button 3X32 causes the relays IP, 2P, 3? and 4P to be energized so that the code for this push button is Similarly, depression of the push button SXBA causes the relays IN, 2P, 3P and 4N to be energized from which it is apparent that this transmits a code of and the depression of push button 3253B causes the relays IN, 2P, 3P and AP to be energized, thereby resulting in a code of The relay CSP may be said to be a complete-code relay which is energized only when one and only when one relay of each pair is energized providing that the delivery relay DEL is then deenergized.

Referring now to Fig. 4A, in this figure has been illustrated conventionally a code type communicating system of the type more fully described in the application of Phinney, Ser. No. 111,671 filed November 19, 1936, to which attention is directed for a detailed description thereof. Briefly stated this system comprises line wires IL and 2L extending along the single track section from the west interlocking plant shown in Figs. 1 and 2 to the east interlocking plant shown in Figs. 6 and '7. The line wire 2L has included in series therein line relays F and F located at these interlocking plants, respectively. At the west station is located a line battery LB and at the east station is located a line battery LB In practice the line battery LB has a larger number of cells than the line battery LB so that if both of these batteries are included in the line circuit in opposition at the same time the line battery LB will dominate the line battery LE this dilference in voltage is resorted to so that if both the east and the west station attempt to transmit a code to the other station at the same time the battery LB will be overpowered by the battery LB resulting in giving the west station priority as to the use of the line circuit, all as described in detail in the Phinney application above referred to.

The code type communication system illustrated is one of the types in which if a code is transmitted from the west" station to the east station the lock-out relay LO at the east station will be energized and the lock-out relay LO at the west station will be deenergized. In other words, the look-out relay locks out the transmission of an indication and renders the station at which such lock-out relay is energized capable of receiving such indication. The relay the transmission of a' code from the station west to the station east. The relays BZ and B Z are employed to signify that an incompleteicode has been transmitted as more fully described in the above mentioned Phinney application. At the right-hand end of Fig. 4A has been illustrated relays 3DS 3DS I-IDS and SD8 These relays may be said to be storage relays associated'with the'code type transmitting system shown in this Fig. 4A and are used for the purpose of storing a code which has been transmitted by the code communication system for temporarily storing this code until such code can be stored in one'of the storage relay banks illustrated in Fig; 5 of the drawings.

Referring to Fig. 5, this figure illustrates two code storage banks, designated .storage bank 2 and storage bank I, for storing the train destination or train description of two trains following each other through the single track section. The first train will be stored in the storage relays IDSI, IDSZ, IDS3 and IDS4 of storage bank I, whereas the second train will be stored in the storage relays ZDSI, 2DS2, 2DS3 and ZDSA of storage bank 2. Each of these code storage units is provided with a transfer relay DP and a transfer repeater relay DPP. The transfer relay DP in each case when energized prevents the transfer of a train description code to the storage bank with which it is associated and the transfer repeater relay DPP is used to 7 enable a code to be stored in the train'describer C is a starting relay which if energized will start bank next in the rear. Although only-two train describing banks have been illustrated in Fig. 5 it should be understood that there should be as many train describing relay banks as the maximum number of trains that, will be able to cocupy the single track sectionconnecting the two interlocking plants at one time. In order to determine when the storage bank I including storage relays IDS shall control the east interlocking plant located at the east end of the single track section and also when the train description stored therein shall be cancelled, suitable track repeating relays repeating the action of the track relay 3T are employed. These track repeater relays have been designated STPA, 3TPB and 3TPC. The"storage bank I has also associated therewith a-n executing relay IDPA. This relay IDPA is employed to allow a momentary impulse of current to flow only over its front contact 98 for the purpose of controlling the NX interlocking system located at the east end of the single track section and for determining the transfer of a train destination from storage bank 2 to storage bank I through the medium of its contact IE9 in a manner more fully described hereinafter.

Operation of the system of Figs. 1, 2, 3, 4A, 5, 6 and 7.-Let us assume that there is a class No. I numbered train to the rear of the signal SI of the west interlocking plant illustrated in Figs. 1 and 2, and that the operator wishes this train to pass on to the track No of the east interlocking plant illustrated in Figs. 6 and '7. The operatorwill depress the entrance push button INB (see Fig. 1) resulting in the energization of the relay INR. through an obvious circuit. Picking up of the relay INR closes its stick contact I50 as a result of which the relay INR is stuck up, through a stick circuit circuit including the front contact I49 of the track relay IT and the stick contact I58. in series. With the relay INR energized the relay IY is energized through a circuit including front contact I61 of relay INR and back contact I48 of relay IR. The operator could now depress the exit push button 3XB and thereby cause operation of the track switch ITS to-its normal position, if it has not already assumed that position, to cause clearing of the signal SI, but since the operator is desirous of also controlling the NX interlocking plant at the east end of the single track section he will not depress the push button 3XB but will depress the proper exit push button illustrated in Fig. 3 of the drawings. Since the operator desires to send'a class I numbered train to the track No, used only for numbered trains, he will depress the exit push button 3XBI (see Fig. 3).

Depression of this push button 3XBI causes the push button storage relays IP, 2P, 31? and 4N to be picked up through obvious pick-up circuits including back contacts I5I, I52, I53 and I54 of the complete-code relay CSP. With these push button storage relays once picked up they are stuck up through stick circuits including thei r stick contacts and including a contact of the cancelling push button CPB, wire I22 and back contact I55 of the executing relay EX (see Fig. 4A). With the relays IP, 2P, 3P and 4N picked up the complete-code relay CSP is picked up through a pick-up circuit including front contact I56, back contact I51, front contact I58, back contact I59, front contact I60, back contact I6I, back contact I82, and front contact I63 of relays IP, IN, 2P, 2N, 3P, 3N, dP and 4N, respectively, and then passing through back contact I64 of the delivery relay DEL to the winding of relay CSP. The relay CSP will therefore be energized and will then be stuck up through a stick circuit including its own front contact I65 in multiple with back contact I64 of relay DEL.

With the relay CSP normally in its deenergized position the slow acting relay SR is energized through a circuit including back contact I66 of delivery relay DEL, and back contact I14 of the relay CSP. Picking up of the relay CSP in response to a complete code stored in the push button storage bank, as just explained, causes a momentary fiow of current through the following circuit: beginning at the terminal front contact I61 of the relay INR, wire 2I8, back contact I48 of the relay R front contact 2I3 of the relay IY, winding of the exit relay 3XR, back contact I68 of relay 3NR, normally closed push button contact 3XB, wire I69, front contact I19 of the relay SR, front contact I14 of the relay CSP, and back contact I65 of the delivery relay DEL to the other terminal Current will flow through this circuit only during the drop-away period of the slow dropping relay SR. The momentary flow of current in the exit relay SXR causes this relay to pick up, after which it is stuck up through a stick circuit including contact I61 of relay INR, contact I48 of relay R contact 2I3 of relay IY and contact I1I of relay SXR, in series. Relays 3XR and IY now being energized causes the normal relay N tobe energized through a circuit including the front contact I12 of relay SXR, front contact 2I1 of the relay IY, and back contact 24I of the relay R in series. Picking up of the relay NI causes energization of the switch control relay IWZ and the operation of the switch machine ISM through front'contact 244 of relay IWZ, all in a manner as already described in connection with the east interlocking plant illustrated in Figs. 6 and '1 of the drawings.

The completion of the movement of the track switch to its normal position causes opening of the back contact 245 of the correspondencerelay INCR as a result of which the lock relay IL'is deenergized. Dropping of the lock relay IL closes its back contact 258 which in turn closes an energizing circuit for the signal relay IG, which circuit includes front contact 25I of the relay SXR, back contact 259 of the relay IL, front contact 249 of the relay INCH, back contact 248 of the relay IXR, and front contact I13 of the relay INR, through winding of the relay IG, to Energization of the relay IG results in clearing of the signal SI. With the signal Si now cleared the train in question may proceed into the single track section over the track switch ITS in its normal position.

Entrance of the train upon the track circuit containing track relay IT causes deenergization of this track relay IT, which, among other things, results in the opening of its front contact 223 included in the energizing circuit for the lock relay lL. This dropping of the track relay IT also causes it to close its back contact I15 (see Fig. 3) which results in energization of the delivery relay DEL through a circuit including its back contact I15 and including front contact I16 of the relay CSP. With the delivery relay DEL once energized it is stuck up through a stick circuitinclucling its own front contact I11 and also including the front contact I16 of relay CSP. V

Picking up of the delivery relay DEL causes closure of its front contact I18, and also causes the opening of its back contact I64 shunted around the stick contact I65 of the relay CSP, thereby leaving the relay CSP only energized through its stick circuit heretofore traced. Closure of the front contact I18 of the delivery relay DEL causes initiation of the code type communicating system illustrated in Fig. 4A by closing the following initiating circuit of the communication system: beginning at the terminal front contact I18 of the relay DEL, wire 64, back contact I19 of the look-out relay LO, back contact I 86 of the cycle demarking relay SA, back contact I8I of the incomplete code relay BZ, through the winding of the starting relay C to the other terminal Picking up of the starting relay C will cause the communicating system to be set into operation, resulting in the energization of the look-out relay LO at the east end of the code communication system and also resulting in the energization of the cycle demarking relays SA, SB and SB With the relay SB energized the starting relay C is stuck up through a stick circuit including the front contact I82 of the relay SB, and the stick contact I83 of the relay C.

During operation of the code type communication system and during the period of energization of the first stopping relays IV and IV at opposite ends of the line circuit IL-2L is energized by current of positive polarity, because the pole changing relay PC is energized during this period. The energizing circuit for this relay PC with the relays VP and IV energized may be traced as follows: starting at the terminal back contact I84 of the relay LO, front contact I85 of the relay 0, front contact 836 of the relay VP, back contact I81 of the relay 4V, back contact I88 of the relay 3V, back contact I69 of the relay 2V, front contact I90 stepping relay IV energized. This circuit may be traced as follows: starting at the terminal polar contact- I92 of the relay F in its right-hand position, front contact I93 of the re-' lay L back contacts I94, I95 and I95 of relays 4V 3V and 2V respectively, front contact I91 of the relay IV back contact I99 of the relay PSP, through the winding of the storage relay 3DS to the other terminal In a similar manner the energized condition of relays 2P and SP results in the picking up of the relays 3DS and 3DS during the second and third impulse periods of the code communication system during which the stepping relays 2V and 3V are energized, respectively. Since the storage relay 4P is deenergized and its contact 200 is in its retracted condition'the pole changer relay NC will be energized during the fourth stepping period of the communicating system through the medium of back contact 200 of relay GP and wires I5 and 202 which results in movement of the polar contact I92 of the line relay F to its left-hand position as a result of which the code storage relay BDS remains deenergized.

Each of the code storage relays 3DS 3DS and 3DS as it is energized is stuck up through a stick circuit including its stick contact and also including the front make-before-break contact 20I of the cycle demarking relay 513 During the fifth step of operation of the code type communication system the execution relay EX picks up and this causes an execution circuit to be closed including the front contact 203 of the look-out relay L0 and front contact 204 of the execution relay EX The closure of this execution contact 204 causes the terminal of the battery to be connected to each of the front contacts 205, 206, 201 and 285 of the storage relays 3DS SD8 3DS and 3DS respectively. Since both the storage bank I and the storage bank 2 are empty and the transfer relays IDP, IDPP and 2DP are deenergized, the storage relays IDSI, IDS2 and IDSS (see Fig. 5) will be energized during this fifth step through the following three pick-up circuits: (1) the circuit including contacts 203 of relay L0 front contact 204 of relay EX front contact 205 of relay 3DS wire I2, back contact I6 of relay ZDP, and back contact 17 of relay IDPP, back contact I8 of relay IDP through winding of relay IDSI; (2) a circuit including front contact 203 of relay L0 front contact 204 of relay EX front contact 206 of relay 3DS wire I3, back contact I9 of relay ZDP, back contact 80 of relay IDPP, back contact 8| of relay IDP, through winding of relay IDS2; and (3) the circuit including front contact 203 of relay L0 front contact 204 of relay EX contact 207 of relay 3DS wire I4, back contact 82 of relay ZDP, back contact 83 of relay IDPP, back contact 84 of relay IDP, windin of relay IDS3. With these storage relays IDSI, IDS2 and IDS3 of storage bank I now energized they will be stuck up through stick circuits including their stick contacts and including front contact of the track repeater relay 3TPB. With the storage relays IDSI, IDS2 and IDS3 energized the train describer lamp I will be energized through a circuit including front contacts I03, I04 and I05 of relays IDSI, IDS2 and IDS3, respectively, and including back contact I06 of storage relay IDS4.

Upon completion of the cycle of operation of the code type communication system shown in Fig.'l-A this system will be returned to its normal position, in which position the cycle marking relays SA, SB and SE will all be returned to their deenergized position, in a manner more fully described in the 'Phinney applications. Dropping of the cycle demarking relay SB results in the opening of its front contact 20I thereby opening the stick circuits for the storage relays SDSI, 3DS2 and SD83, unless the stick circuits for these relays 3DSI, 3DS2 and 3DS3 are maintained closed at front contact 209 of the relay 2DPP. The closure of the back makebefore-break contact 20I of relay SE will result in the energization of the relay PSP in the event that the storage relays 3DS iiDS and 3DS are still in their'energized condition, and this relay PSP will then be stuck up through a stick circuit including its own front contact 2I0.

During the fifth step of operation of the code communication-system, namely, during the time that the execution relays EX and EX are energized the lifting of the back contact I55 of the relay EX caused the stick circuits for the relays IP, 2P, 3P and 4N, heretofore traced, to be broken at this back contact I55. This, of course, resulted in the deenergization of these relays P and N and in turn resulted in the deenergization of the complete-code relay CSP, which in turn locking system to return to its normal condition, except that the track switch will remain in the last operated position. The train in question is now occupying the single track section and hasnot yet reached the east interlocking plant located at the east end of the single track section and illustrated in Figs. 6 and '7 of the drawings. The class 1 numbered train is however registered in storage bank I by the energized condition of relays IDSI, IDSZ and-IDS3. With these relays IDSI, lDSZ and IDS3 energized the following energizing circuit is closed for the transfer relay IDP: beginning at the terminal back contact 210 of relay LO (see Fig. 4A), or back contact 21! of relay EX delay pick-up wire Pu, back contactilil of relay ZDPP, back contact 89 of relay ZDP, back contact 90 of relay lDPP, front contacts 9!, 92 or 93 of relays lDSI, IDS2 or IDS3 through the lower winding of the relay IDP. With this relay IDP once energized it is maintained energized through a stick circuit including its own front contact 94 so long as any one of the relays IDS remain energized.

Let us assume that the operator at the east interlocking plant is absent or for some other reason it is desired to have this interlocking plant, controlled by the operator located at the West interlocking plant illust'ratedin Figs. 1

and 2, and for this reason the operator at the east interlocking plant has moved his selecting lever ASL to its left-hand sorting position. With the selecting lever ASL in its left-hand position and with the code stored in storage bank I the following circuit for energizing the relay IIXP is closed the moment the transfer relay IDP was picked up in response to the reception of the train description in storage bank I; and before the executing relay IDPA, which is slow dropping, had sufiicient time to drop away: starting at the terminal contact of the selecting lever ASL closed in its left-hand position, front contact 96 of the track relay 3T, wire 91, front contact 98 of the executing relay IDPA, front contact 99 of the transfer relay IDP, front contact I 9!) of the storage relay IDSI, front contact I ill of the storage relay IDSZ, wire I92, through the winding of the relay IIXP to the other terminal Picking up of the relay IIXP will close an energizing circuit for the normal relay IBNR, including front contact 57 of the relay IIXP, back contact 30 of the signal control relay IOG, normally closed contact SI of the push button IIINB, winding of the relay IONR. With the relays IIXP and IGNR. now energized the following energizing circuit is closed for the exit relay IIXR: beginning at the terminal front contact 35 of relay IDNR, back contact 58 of relay 3N, back contact 59 of relay IINR, and front contact 68 of relay I DE. The entrance relay IQNR is of course stuck up through a stick circuit including its own front contact 33 and the front contact 32 of the track relay ST, and the exit relay IIXR is stuck up through a stick circuit including the front contact 35 of the entrance relay IBNR and including the stick contact BI of the relay IIXR. With these relays IGNR and I IXR energized the switch machine 38M will be operated to its reverse position 'all in a manner as already described hereinbefore. When the track switch has been fully operated to its reverse position and has been locked the: signal SI will be cleared through the medium of energization of Z.

IDP. Picking up of the transfer repeater relay IDPP transfers the code message wires 12, 13, I4 and 15 from the storage bank I to the storage bank 2 through the medium of contacts 11, 80, 83 and I39 of this relay IDPP, so that the reception of a second train description will be stored inthe storage bank 2 instead of the storage bank I.

Let us now assume that the operator wishes to send a class A lettered train from the track directly in the rear of the signal S2 (see Fig. 1) into the lettered track Le shown in Fig. 6 of the drawings. In order to accomplish this the operator must depress the entrance button ZNB followed by depression of one of the lettered exit buttons 3XBA or 3XBB. Since it is however assumed to be a class A lettered train, he will depress the push button 3XBA. Depression of the push button 3XBA results in energization of the relays IN, 2P, SP and 4N, signifying code which in turn results in the energization of the relay CSP, all in a manner as already described. Depression of the push button 2NB resulted in energization of the relay 2NR, which relay 2NR was then stuck up through a stick circuit including its stick contact 213 and front contact 214 of the track relay IT. Picking up of the complete-code relay CSP results in the closure of the following circuit for the exit relay .iXR, beginning at the terminal front contact 214 of the relay 2NR, wire 2 I 9, back contact 275 of the relay N back contact 2I3 of the relay IY, winding of the relay sxa, back contact I68 of the relay 3NR, normally closed push button contact 3X8, wire IE9, front contact I'll] of the relay SR, front contact I'M of the relay CSP, back contact I66 of the relay DEL, to the other terminal The relay SXR will of course then be stuck up through a stick circuit including its stick contact III. With relays ZNR and 3XR energized and with the relay .IY deenergized the reverse relay R is energized through a circuit including front contact I12 of the relay SXR, back contact ZI'I of the relay IY and back contact 253 of the relay N Energization of the relay R will, of course, through the medium of relay IWZ operate the switch machine SM to a reverse position in a manner as already described in connection with east interlocking plant shown in Figs. 6 and 7.

As the second train progresses past the signal S and treads upon the detector track circuit containing track relay IT, the closure of back contact I15 of this track relay (see Fig. 3) will result in the energization of the delivery relay DEL and will result in the initiation of the code type communication system shown in Fig. 4A to result in energization of the storage relays 2DS2 and 2DS3 (see Fig. 5) all in a manner as already described in connection with the first train which is occupying the single track section. Storage of the train description of the second train in the storage bank causes energization of the transfer relay ZDP through an obvious circuit including back contacts 279 or relay L0 or 2' of relay EX all in a manner as already described for storage bank I. With the transfer relay ZDP now energized and stuck up through its front contact 89 the transfer repeater relay 2DPP is energized through the front contact 275 of the relay 2DP. Picking up of the transfer repeater relay ZDPP causes closure of its front contact 209 so that if a third train description is transmitted by a code type communication system while the storage bank I and the storage bank 2 both have a train destination description stored therein, the third train will be described in the storage relays 3DS shown in Fig. 4A of the drawings, and one or more of these relays 3DS will be stuck up through stick circuits including this front contact 299 of relay ZDPP.

Let us now assume that the first and the second train are still occupying the single track section and that the operator at the west interlocking plant desires to have a third train enter the single track section. Let us further assume that this third train is a B class lettered train and that for that reason the operator depresses an entrance button INB or ZNB and the exit push button 3XBB. This will result in the transmission of a code of all in a manner as already described, and will result in the energization of the relays 3DS SDS and 3DS (Fig. 4A) and with these relays once energized they will be stuck up through a stick circuit including their respective stick contacts and including the front contact 299 of the transfer repeater relay 2DPP.

Reviewing for a moment, there are now three trains occupying the single track section and the code is stored in storage bank I, the code is stored in storage bank 2, and the code is stored in the storage bank 3, and the lamps I, A and B (lamps A and'B not being shown) of storage banks I, 2 and 3, re-

spectively, are illuminated.

With the signal SIO now clear as above pointed out the first train of the three trains moving from west to east over the single track section may accept the signal SID and pass into the numbered track No. As soon as this first train treads upon the detector track circuit containing track relay 3T the front contact 32 of this track relay 3T is opened thereby deenergizing the entrance relay IONR and in turn deenergizing the exit relay IIXR. as a result of which the signal SIB is returned to its stop position. The track switch 3TS will, of course, remain in its reverse position until again operated.

Another function performed by the dropping of the track relay 3T in response to entrance of the first train upon the detector track circuit associated with track switch 3TS resides in the cancellation of the code stored in storage bank I and in the transfer of the train description stored in storage bank 2 to storage bank I and in the transfer of the train description stored in the storage bank 3 to the storage bank 2".

Taking these operating functions up in the order just given, dropping of the track relay 3T will result in closing of its back contact H5, but the closure of this contact H5 will produce no effect because the executing relay IDPA was deenergized in response to the picking up of the transfer relay IDP. Since the train entered upon the track section 3 while the signal SIB was in its clear position and while the front contact I09 of the signal relay IIIG was closed this dropping of the track 3T causes energization of the track repeater relay 3TPA through a pick-up circuit including front contact I08 of relay 3T, front contact I09 of signal relay IOG and wire H0. With this track repeater relay 3TPA once picked up it will remain stuck up through a stick circuit including back contact I08 of track relay 3T, wire I I I and the stick contact I I2 of the track repeater relay 3TPA. Picking up of the track repeater relay 3TPA results, by reason of opening of its back contact 2|, in deenergization of the track repeater relay 3TPB. Dropping of the track repeater relay -3TPB results in the opening of its front contact 85=and in the cancellation of the code stored in storage bank I, it being understood that the transfer relay IDP is now energized and the storage relays of storage bank I are wholly dependent upon their stick circuits for energy.

7 Also, the dropping of track repeater relay 3TPB opens the executing circuit for transferring a train description from storage bank 2 to storage bank I at the front contact I36 of the relay 3TPB. This opening of the stick circuits for the storage relays of storage bank I and the opening of the execution circuit just mentioned is, however, only momentary because the dropping of the track repeater relay 3TPB results in energization of the track repeater relay 3TPC through back contact H3 and results in closure of its contact H4 which may be included in the stick circuits for thestorage relays of storage bank I and also results in the closure of its front contact I I8 which may supply energy to the execution circuit just mentioned. This execution circuit can, however, not be closed at this time because front contact II9 of relay IDPA "is now open.

Cancellation of the train description from the .f-storage bank I results in dropping ofall of the storage relays IDS and in extinguishment of the lamp I, and this also results in the dropping of the transfer relay IDP, because the transfer relay 2DP is now energized and at its back contact 2I'I prevents the stick circuit including the stick contact 278 of relay IDP from being closed. Dropping of the transfer relay IDP results in picking up of the executing relay IDPA through its pick-up circuit including the backcontact 22 of transfer relay IDP. Since the detector track relay ST is still deenergized this executing relay I DPA is stuck up through a stick circuit including the back contact H5 of the track relay 3T, the wire H0 and the stick contact II'I of the executting relay IDPA. With this executing relay IDPA now energized the following executing circuit will transfer the code .stored in storage bank 2" to the "storage bank I, through the following two pick-up circuits: (1) starting at the front contact H8 of the track repeater relay 3TPC, front contact H9 of the executing relay I IDPA, front contact I20 of the storage relay ZDSZ, and back contact 8| of the transfer relay IDP, through the lower winding of the storage relay IDSZ; and (2) starting at the terminal (-I), through front contact H8 of the track repeater relay 3TPC, front contact H9 of the exeouting relay IDPA, front contact I2I of the storage relay 2DS3, and back contact 84 of the transfer relay IDP, through the winding of the storage relay IDS3. These storage relays IDS2 and IDS3 will then be stuck up through stick circuits including their respective stick contacts and including the contacts I I4 of the track repeater relay 3TPC. The train description lamp A is now energized through a circuit including back contact I03 of storage relay IDSI, front contacts I3I and I32 of storage relays IDS2 and IDS3, respectively, and back contact I33 of storage relay IDS I. The transfer of the train description from the storage bank 2 to the storage bank I took? place between the time that the transfer relay IDP assumed its deenergized position to close its back contacts I8, 8|, 84 and I23 and the time when the transfer repeater relay IDPP opened its front contact I01. In other words, as soon as the train destination has been transferred from storage bank 2 to storage bank I and upon dropping of the transfer relay IDPP and the opening of its front contact I01, the storage relays of storage bank 2 are deenergized to wipe out the train destination description stored therein.

It will be noted that the transfer relay IDP must be pickedup through the back contact 90 of thettransfer repeater relay IDPP as a result of which the picking up of the transfer relay IDP will be delayed a short time after energization of the storage relays IDS2 and IDS3. When the transfer relay IDP becomes energized to close its front contact 280 and before the transfer repeater relay ZDPP has become deenergized to open its contact 28I, in response to the dropping of the storage relays of storage bank 2 and in turn the dropping of the transfer relay 2DP, an execution circuit is closed for transferring the train description stored in storage bank 3 to the:storage bank 2. This execution circuit may be traced from through front contact 280 of relay IDP, front contact 28I of relay ZDPP, executing wire 283 through the following three branches: (1) front contact 206 of relay '3DS wireI3, back contact I9 of relay 2DP, and front contact of relay IDPP through the lower wind ing of the storage relay 2DS2; '(2) through front I V contactZO'I of relay 3DS wire 14; back contact 

